Degenerative lumbar spinal stenosis (LSS) is a common, costly, disabling low back pain syndrome affecting elderly patients. Although 30,000 laminectomies are performed annually in the U.S. on patients over 65, at an annual cost of almost one billion dollars, the effectiveness of laminectomy for degenerative LSS has not been examined critically. The goals of this study are to: (1) evaluate the outcome of laminectomy for LSS in terms of pain, function, health status, and resource utilization; and (2) identify clinical, demographic, and technical factors associated with particularly favorable or poor outcomes. Two hundred forty operative and 125 conservatively managed patients with radiologically confirmed LSS will be examined in a prospective multicenter observational study. Baseline information includes sociodemographic, physical examination, radiologic, and psychosocial data and Sickness Impact Profile (SIP) score. Outcome data is obtained at 6, 24, and 36 months and include complications, pain, and SIP scores as the principle measures of effectiveness. Analyses will identify predictors of particularly favorable or unfavorable outcomes. The results of this study should enhance doctor- patient decision making about surgery for this disabling condition.